Question

An air bubble in a glass slab with refractive index 1.5 (near normal incidence) is 5 cm deep when viewed from one surface and 3 cm deep when viewed from the opposite face. The thickness (in cm) of the slab is 

(a) 8 

(b) 10 

(c) 12 

(d) 16

Answer 1

Correct option  (c) 12 

Explanation:

l = length of the slab

x = position of air bubble from one side

As per question, total apparent length of slab = 5 + 3